Abstract: A ball sealer consists of an inner spherical rigid core of a desired density and an outer resilient or compliant continuous layer of uniform thickness which is comprised of a pair of hemispheric caps positioned about and secured to the core and to each other.The ball sealer is formed by molding a first cap in the form of a hemisphere having a central cavity adapted to receive one-half of an inner core. The cap is placed in a cavity in the bottom plate of a mold and the outer surface of an inner core or the inside of the cavity of the cap is coated with an adhesive that will bind the cap to the core. The core is then placed within the cavity of the cap. A cavity plate having a hemispheric cavity is then positioned on top of the bottom plate of the mold with exposed upper half of the inner core received within the cavity of the cavity plate.